<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>animation</title>
        <link rel="stylesheet" href="animation.css">
    </head>
    <body>
        <div></div>
        <a href=" " class="btn">发光的button</a>

        <div class="round"></div>



    </body>
</html>















































